Total temporomandibular joint (TMJ) replacement, unlike total hip and total knee replacement, has suffered from its poor long-term (> 5 years) success rate. Many difficulties with TMJ alloplastic implantation are due to its anatomic constraints and inherent high joint forces associated with function and parafunction. Naturally growing bone to regenerate the joint may provide an improved intervention over other implants used in TMJ implant surgery. The purpose of this research proposal is to test the central hypothesis that a biomimetic hydroxyapatite-gelatin (HAP-GEL) nanocomposite is an osseous inductive material that can serve as a good load bearing scaffold to carry osteogentic cells and grow bone. If this concept is approved in vitro, the material can further be applied to animal models for TMJ regeneration. To test this hypothesis, three specific aims are proposed: Specific Aim 1. Optimize hydroxyapatite-gelatin matrix to maximize the adhesion of osteoblasts to the material and mechanical strength of the material, and to determine its degradation rate. Specific Aim 2. Design a 3D porous scaffold of the nanocomposite to approximate the dimensions (2 cm x 1.5 cm x 0.8 cm) of the human condylar head. Specific Aim 3. Cultivate the 3D scaffold with osteogenic cells. Hydraulic molds and selective solid etching process will be developed and used to fabricate 3D nanocomposite scaffolds. Pore size and seeding cell density will be designed so that osteoblasts adhered inside the scaffold will be nurtured and proliferate. Preliminary tests using rat mesenchymal stem cells will direct our future studies on the application of the HAP-GEL nanocomposite to stem cell based technology. The significance of this proposal is also enhanced by the many downstream benefits that follow from a load bearing scaffold, including the development of restorative grafts of periodontal structures and alveolar sockets with the immediate placement of oral implants.